In "Egoism and Moral Skepticism," James Rachels discusses psychological egoism, which is the view that each person has one ultimate aim: her own welfare. Proponents of psychological egoism claim that apparent acts of altruism are merely apparent, since those who act in apparently altruistic ways derive pleasure from doing so. That is to say, acting in apparently altruistic ways makes people feel good, which means that they are not really altruists, but rather egoists, since they act in such ways in order to feel good about themselves, rather than truly help someone in need.
This seems very odd, however. A person who is truly an egoist is a person who has no concern whatsoever for the welfare of others. In that case, how can an egoist derive any pleasure from acting in apparently altruistic ways?
In other words, proponents of psychological egoism seem to be making the following causal claim. They claim that an apparently altruistic act performed by Egoist causes Recipient to feel good, which in turn causes the Egoist to feel good about herself.
The second arrow in this causal chain, however, seems very mysterious. If a person is truly an egoist, then it is not clear how that person can be caused to feel good by making other people feel good, since, by hypothesis, an egoist is a person who doesn't care about the welfare of others. Can proponents of psychological egoism make this claim less mysterious?